A stunned Lewis Hamilton scorched to his third pole position in a row for Mercedes in searing track temperatures at the Hungarian Grand Prix on Saturday.

The 2008 Formula One world champion, a triple winner in Hungary with McLaren, lapped the circuit with a best time of one minute 19.388 seconds to deny Red Bull's Sebastian Vettel the top slot.

"Are we on pole?," the Briton shouted over the radio on his slowing down lap at the Hungaroring. "Yeah, we're as surprised as you," came the reply.

Triple world champion Vettel, who leads Ferrari's Fernando Alonso in the standings by 34 points after nine of 19 races, could manage only 1:19.426 with the track temperature hitting 50 degrees earlier in the session. He starts second.

Hamilton had never before in his stellar career taken three successive poles and his fourth of the season took his overall tally to 30 - one more than the late Argentine five-times champion Juan Manuel Fangio.

"With the temperatures, it was pretty tough. I was really surprised when they said I got pole. I didn't feel like that was a great lap," Hamilton told reporters.

"I was expecting Sebastian to get it," added the Briton who won from pole last year in Hungary but has yet to win a race since leaving McLaren at the end of the 2012 season.

Frenchman Romain Grosjean qualified third for Lotus with Hamilton's German team mate Nico Rosberg fourth. Alonso, who has not started on pole for more than a year and turns 32 on Monday, will start fifth.

"It is stupid to sit and say, we should have done this and we should have done that," said Vettel who dominated Friday practice but has never won in Hungary.

"Mercedes have good pace in qualifying so you have to be fair and respect that. I would have loved to have been a little bit faster and on pole but we have a good car and are in a good position.

"We should have a good race tomorrow and I am quite confident."

The race will be the first using the new Pirelli tyres, which have been changed to marry the current compounds with last year's structure after a spate of blowouts in Britain last month threw the sport into crisis.

Raikkonen SixthMercedes were the only team who did not try out the new tyres in Silverstone last week, as a punishment for a 'secret' test with Pirelli in Spain in May, but their absence did not appear to hurt them.

"We brought some upgrades this weekend, the guys are working hard and it's a result of all the hard work they've put in," said Hamilton.

Grosjean's team mate Kimi Raikkonen, third in the overall standings and 41 points behind Vettel, qualified sixth while Australian Daniel Ricciardo continued to impress in eighth place for Toro Rosso.

Compatriot Mark Webber, the man Ricciardo hopes to replace at Red Bull next year, starts 10th after suffering KERS problems from the second phase of qualifying.

McLaren's hopes of an improved showing at a circuit that has been good to them in the past, with six wins in eight years, faded with Mexican Sergio Perez qualifying ninth and Britain's Jenson Button 13th.

The big loser in the first phase was Force India's Paul Di Resta who qualified 18th and was baffled at the car's lack of performance.

"Where did the grip and tyres go?", the Scot asked his team over the radio. "Looks like we've got some work to do," they replied.